Foot/Lower Leg Wounds and Treatment

When you find your horse with a severe wound of the hoof or lower leg, you likely want to clean it up, remove any foreign matter such as fence wire, and apply antibiotics, right? However, this could make evaluation by your veterinarian more difficult, said Earl Gaughan, DVM, of Kansas State University's College of Veterinary Medicine at the 15th annual Bluegrass Laminitis Symposium January 21-23.

"Try to get the client to not topically medicate the wound, so you can really see what's going on," he began. "The key to success is to see the wound as it happened, not covered with purple, green, blue, or whatever colored dressing or powder."

He also encourages clients to leave any penetrating objects such as nails or wire in place so that the veterinarian can see visually and via X rays how deep the object penetrated, and treat those structures accordingly. If transport is necessary, he suggested clipping off the object near the skin if possible, and wrapping the area in a bath towel to pad it before shipping the horse to a hospital.

The veterinarian's physical examination of the wounded horse should evaluate three things: The systemic health of the horse (i.e., has the wound resulted in significant blood loss, etc.? Does overuse of the contralateral limb risk unilateral laminitis?), the wound site (what tissues are involved and has any tissue been lost?), and the region surrounding the wound (has the wound significantly damaged the vascular system around the wound?). Physical manipulation is also important, as this can reveal excessive laxity of the limb due to transected support structures.

If it's a ventral (solar) wound, you might have to deal with penetration to the coffin bone (P3), which is not uncommon and can result in fracture or osteitis of P3 (see article #2771 for more on septic osteitis of P3). "After several of our cases, we've become optimistic about losing parts of P3 to these problems and still ending up with a sound horse," Gaughan commented.

"Some of these wounds don't look like they go anywhere dangerous, but if you wait for the horse to tell you, then you might be behind and success might not be possible," Gaughan cautioned. "If you have any doubt about a wound, get attention to it early. Also, you can't go wrong assuming that a joint or other synovial structure is involved (and treating accordingly). If you wait to confirm this, it might be too late."

Injecting the joint and/or the wound with positive contrast medium can help identify whether the joint has been compromised, or injecting a sterile solution (lactated ringers or saline) into a non-wounded aspect of the joint to see if the solution exits the wound. Flushing of compromised joints, preferably arthroscopically to visualize any debris that might need to be removed surgically, is important.

Thermography can be another valuable tool for assessing blood flow distal to the wound. If there is little to no blood flow beyond the wound (noted by cold, dark areas on the thermograph), then the prognosis is very guarded. "This is a good assessment tool for detecting evidence that may indicate that treatment will not likely succeed before a lot of investment in treatment," Gaughan commented. "But keep in mind that wounds are dynamic, and things can change from day one to five, or seven." Also, ultrasonography can help detect foreign material, gas pockets, and abnormal fluid accumulation in and around the wound.

Moving on to treatment, cleanliness is naturally next to godliness, but this doesn't include topical medications or antibiotics. "It's vital to maintain good hygiene--usually clean and covered is the way to go--but my advice is to back off of any topical medications initially, until you can see what tissue will survive and what won't," Gaughan explained. "I've seen P3s mostly lost to bone necrosis from excessive Kopertox going through a wound. Also, once granulation tissue covers deeper structures, antibiotics might not continually be necessary because the granulation tissue is providing a barrier to the environment.

Gaughan said that it is important to support tissues that can heal "to reduce the influence of the great motion and tension in the distal limb. There's a lot of concern with covering these wounds, but it can help a lot especially when movement is not allowing the wound to heal," he said. He uses foot casts for some of these horses, which he said can last two weeks without major difficulty. "The immobilization of the foot cast does wonderful things for these wounds, and I feel comfortable with putting horses in these casts on a trailer to go home," he added.

"Be careful with Bute (phenylbutazone)," he continued. "If you have synovial (joint) compartment involvement, Bute can make a horse look better than the true state of treatment response. We tend to give Bute for 36 hours and then give the horse 12 hours off of it to see if lameness improvement is due to Bute or to treatment and healing."

Shoeing can sometimes be done around foot wounds, but Gaughan warns against covering such wounds with acrylics, citing a risk for abscess formation due to the moisture in the wound. Hospital plates have been very useful in his practice, especially when frequent debridement of tissues near the sole is necessary.

"The prognosis for these horses varies depending on what structures were injured, but often patience (during the often lengthy healing process) is rewarded," he concluded.

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